Yep nicely answered Glenn - Mike you asked a tricky question to give a short answer too but Glenn has done it beautifully
thanks I have a better grip on it now as well
just thought i would add - I know a lot of people have SN including you Mike? - I use the now old 4.5.2 pro
it has a neat feature that allows you to graph varying aspects of orbits - including the altitude of some heavenly bodies with regard to your location. it is not without bugs I suspect - but seems roughly right?
all i am saying is you can check easily the varying altitudes over a period of time - I assume you are mostly interested in imaging circumstances Mike?
EDIT: I notice the altitude figures are hard to see in this reduced and shrunk for the web giff - the highest one on the left is indicating 50 deg whilst the next one down says 20 deg then 10>5>2